Early work in any trade is mostly junk, and academia no exception.
But the process of creating that work, engaged throughought that process with those purported to be more practiced, is usually pretty good at seeding enough expertise and confidence that you might be able to proceed more independently and with real novelty, or might at least be prepared to share the trade with others new to it.
That's the point of those years, and so it's more than a little ironic that AI is being used to undermine a practicing expert while simultaneously eroding the traditional process for becoming one by making it so easy to just generate slop and engage with hallucinations than to actually practice writing deep work or engaging with primary sources.
The whole idea of a PhD is acknowledging that a person has made a meaningful contribution.
It is not "early work" but the end of early work. The masterpiece: the piece of work that proves a subject has mastered their craft.
If you're still producing junk you haven't earned your PhD.